A multiple input multiple output, multiple input multiple output (MIMO) system is a frequency multiplexing system with a high spectrum utilization rate. Compared with a single input single output, single input single output (SISO) system, a spectrum utilization rate of an M*N MIMO system is Min(M,N) times of that of the SISO system, where M and N are integers greater than zero, M refers to the number of transmitting antennas, and N refers to the number of receiving antennas.
According to a radio frequency structure and spacing between antennas of the system, the MIMO system may be categorized into a centralized MIMO system and a distributed MIMO system. Generally, spacing between antennas of the centralized MIMO system is relatively small, for example, one base station connects to a plurality of antennas, and the plurality of antennas is usually arranged in one place. Spacing between antennas of the distributed MIMO system is relatively large, for example, one antenna connects to one base station, and spacing between antennas is relatively large because a distance between base stations is relatively large. Compared with the centralized MIMO system, the distributed MIMO system can obtain a higher diversity gain, which is an important development trend of a wireless communications MIMO system in the future.
However, using an existing frame synchronization method may cause a frame synchronization error in the distributed MIMO system. Therefore, a frame synchronization method that can adapt to the distributed MIMO system is required.